Telephone



I. BERDELL. TELEPHONE.

1Application filed Mar. 28, 1896.)

(No Model.)

wiimeoaw Patented Jan. l0, I899.

- with a non-conducting bushing 4.

STAES TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 617,433, dated January 10, 1899.

Application filed March is, 1896.

To all whom it may concern:

Be it known that I, THEODORE BERDELL, a citizen of the United States, residingin Summit, Union county, State of New Jersey, have invented a new and useful Improvement in Telephones, of which the following is a specification.

My invention relates especially to instruments employed for transmitting and receiving tones, particularly of articulate speech, the present invention being an improvement upon that shown and described by me in an application filed December 27, 1895, Serial No. 573,433, and has for its objectthe provision of a very simple telephonic instrument.

To attain the desired end, my invention consists in certain novel and useful combinations or arrangements of parts, and peculiarities of construction and operation, all of which will be hereinafter first fully described and then pointed out in the claims. 9

In the accompanying drawings, forming'a part hereof, Figure l is a front elevation of a telephonic instrument embodying my in.- vention. Fig. 2 is a vertical axial sectional view at line a: :0 of Fig. 1. Figs. 3, 4, and 5 are like views illustrating different assembling of .the parts. f

Similar numerals of reference wherever they occur indicate correspondingpartsin all the figures. I

1 is the front diaphragm, made 'of carbon or any other suitable material. This diaphragm is perforated at its center and is mounted upon a metallic or eonductin g screw or pin 2.

3 is a back diaphragm or plate preferably made of carbon and provided at its center 5 is an exterior ring of non-conducting ma-' terial which is placed outside of or between phragms or plates are held'together, but insuthe diaphragms, and serves to prevent the escape of the granules 6. 7 is a central ring of non-conducting material or a disk of felt 8, as in Figs. 2 and 5, either arrangement from the center of the diaphragms and in an annulus, as shown.

9 and 10 are the line-wires, the line 9 being electrically connected to the central pin or screw 2, and the wire 10 to the back diaphragm or plate 3.

Serial No. 585,208. No model.)

Such case may be added, if desired,

or the screw 2 may he passed through a nut 11-or a plate of metal purely for thepurpose of electrical connection and be secured on a panel 12, as a door, desk, or any other desirable and convenient location, as illustrated in Fig. of the drawings. 5 an'd 7 have no function in my device other than to hold the annulus of granular material in place. f

It may befound desirabl'ein assembling the parts orattaching the instrument to a support to securethe exterior ring-to the back plate or diaphragm and hold thcsame at any convenient point; but when this is done the front diaphragm is notin any way affected, but remains substantially free at its periphery..

. When constructed and arranged as above described, mytelephonewillbe found very effective, while it is so simple that when assembled for use the parts do not require any special adj ustment-whatever. I

The instrument may be use as atransmitt'er alone or as a transmitter and receiver, as

setforth in my application, Serial No. 573,433,

hereinbefore refered to. I

My construction of thetelephone differs from previous arrangements, as the "dialated fromcach other, whereas in said previous constructions the diaphragms are not held together. By my arrangement a greater range of transmission is obtained, as. it is equally effective for a whisper or a shriek.

The instrument is extremely sensitive and will transmit perfectly when the speaker is located ten or twenty feet away from it and uses or-' dinary conversational tones, and talking in a The rings very loud voicenear the transmitter .Wiii not w supported and free to vibrate at their periphcries, in combination with granulated material located between the diaphragms, substantially as shown and described.

2. In a telephonic instrument, two diaphragms secured together and supported at,

their centers, and insulated from each other, in combination with an annulus of granulated material held between the diaphragms, substantially as shown and described.

, 3. In a telephonic instrument, two diaphragms secured together" at their centers while free to vibrate at the edges, insulated from each other, and provided with suitable electrical connections, in combination with an inner ring, an annulus of granular material, and an outer insulating-ring confining the granular material between the diaphragms, substantially as shown and described. 7

4. In a telephonic instrument, the combination of an outer diaphragm held at its center by a conducting-support; an inner 'diaphragm or plate mounted upon an insulating bushing,;through which the said conductingsupport passes; and an annulus of granular material held between the two diaphragms substantially as shown and described.

In testimony that I claim the foregoing I hereunto set my handin the presence of two witnesses. I THEODORE BERDELL.

Witnesses: r

A. M.-P IEROE,, 

